With a mixing system, a mixing module, for example, is supplied through two separate circuits in each case with a substance to be mixed. In this way, the mixing module takes a proportion of the different substances to be mixed in order to enable a mixed substance with a required character to be produced. Several valves for distributing and conducting or mixing the various substances are required for this purpose. This makes the mixing system or the mixing module complicated and not cost effective. The control of the mixing system is impractical due to the use of a large number of valves. Furthermore, to protect a mixing module or compensate for the circuits, a mixing path in the mixing system is frequently bridged by one or more bypasses though which a substance to be mixed is passed in each case. The bypass is normally controlled by an extra manual rotary valve and is therefore not variable.
A multivalve has also been developed which combines two valves to form a single valve. The multivalve is provided with two fixed bores, each for a bypass. Although this enables the number of valves used to be reduced, a bypass designed in this way is also non-adjustable. It is desirable for a mixing system to have a variable bypass, with the bypass being automatically adjustable as a function of the mixture settings. The greater the flow of a substance for mixing in a mixing path of the mixing system, the less of the substance flows through a bypass and vice versa. Furthermore, more of the substance automatically flows in the mixing path for mixing purposes if less of the other substance, or substances, flows in this mixing path.